November 21, 2014

China has
sent its "Speedy Vessel" into orbit on Friday, successfully launching the
Kuaizhou launch vehicle with the Kuaizhou-2 satellite from the Jiquan Satellite
Launch Center. Liftoff at 6:37 UTC marked the second launch from Jiquan in less
than 24 hours following Thursday’s Long March 2D launch that lofted the Yaogan
24 reconnaissance satellite. Kuaizhou is
an integrated launcher-spacecraft system that can carry different payload
packages to orbit with launches possible after less than half a day’s notice.
This quick-response launch vehicle was introduced on September 25, 2013 when
the Kuaizhou launcher delivered the Kuaizhou-1 (KZ-1) satellite into orbit.

At
the time, no details on the launch system were available and Chinese officials
only confirmed the satellite’s identity as optical remote sensing satellite.

Image: CASIC

After its first launch, more details became known about the Kuaizhou launch vehicle that stands nearly 20 meters tall using a stack of three solid-fueled stages and an integrated liquid-fueled fourth stage that remains attached to the payload and provides propulsive capability to the satellite over the course of its mission. Using a 1.7-meter diameter solid rocket motor as a first stage, the KZ launch vehicle weighs in at about 30 metric tons and is capable of delivering payloads of up to 430 Kilograms to orbit.

Photo: bbs.9ifly.cn

Kuaizhou prior to KZ-1 Launch

Combining the payload with the upper stage significantly reduces the mass of the spacecraft by cutting payload adapters and separation mechanisms and integrating the attitude determination & control, power, telemetry, control and propulsion systems of an upper stage and satellite into a single unit.The KZ launcher was developed by the China Aerospace Science & Industry Corporation (CASIC) to be ready to launch with short advance notice as part of an effort to create a quick-response launch system for satellites when needed for monitoring of natural disasters or other events of interest. Kuaizhou is launched from a heavy-load truck with erector device which would theoretically enable the rocket to launch from virtually any location. The launcher is capable of remaining in a ready-to-launch mode for extended periods of time to be able to support a launch just hours after the order is given.According to official Chinese media, the first KZ satellite was to be “used to monitor natural disasters and provide disaster-relief information for its user, the National Remote Sensing Center of China.” Information provided later by Chinese sources indicates that the KZ integrated launcher-payload system was being developed for reconnaissance, Earth observation, communications and other purposes.

The Kuaizhou-1 satellite was developed by the Harbin Institute of Technology and carried an optical imaging system using a CCD detector. From its low operational orbit, the satellite was planned to deliver panchromatic imagery at a ground resolution of 1.2 meters and perform multispectral imaging at a resolution of 5 meters. The spacecraft was reportedly capable of conducing off-nadir imaging up to 20 degrees.

Kuaizhou impressively illustrated its capabilities to conduct orbital maneuvers over the course of its first year of operation. Launched into an orbit of 275 by 293 Kilometers inclined 96.7 degrees, the satellite was just a few weeks from orbital decay.

Two days after launch, the satellite performed its first set of maneuvers to enter an orbit of 299 by 306 Kilometers. In the months that followed, KZ-1 conducted an orbital maintenance maneuver every two to four weeks, keeping its mean altitude between 275 and 305 Kilometers. This low operational orbit allows the satellite to acquire imagery at the highest possible resolution. Past optical reconnaissance spacecraft, particularly those of the Soviet Union and Russia, have also operated from extremely low orbits, but their mission was usually limited to a few weeks or months due to the increased propellant consumption when maintaining an orbit in a high-drag environment. Kuaizhou-1 on the other hand, managed to perform 20 orbit maintenance maneuvers over its first year of operations. Notably, many of these maneuvers were of different magnitudes - indicating that, through maneuvering, KZ-1 was setting up favorable observation passes over locations of interest. After one year spent orbiting around 300 Kilometers in altitude, KZ-1 began a campaign to raise its orbit. This process of orbit-raising maneuvers began around September 21, 2014 and KZ-1 is currently in an orbit of 364 by 389 Kilometers. It is likely that the satellite began raising its orbit to enter a low-drag environment and extend its operational lifetime as its propellant supply reaches exhaustion. With KZ-1 demonstrating its new launcher and being put through the paces in orbit, the next Speedy Vessel was ready to set sail and head for orbit. The Kuaizhou launcher carrying the KZ-2 satellite blasted off from a pad at some distance to the two main Long March launch complexes at Jiquan at 6:47 UTC on Friday. According to Chinese news sources, the satellite reached the planned orbit with orbital parameters awaited from U.S. Space Surveillance later on Friday. Like its predecessor, KZ-2 was also developed at the Harbin Institute of Technology and aims to deliver imagery at ground resolutions better than 0.5 meters. Whether it will also operate from a very low orbit with frequent maneuvers remains to be seen.

Plot: Calsky

KZ-1 Orbit Evolution

Photo: National Remote Sensing Center of China

KZ-1 Image of Beijing West Railway Station

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